Cross braces in the form of metal rods are fitted to motorcycle handlebars of a particular, well known configuration involving four bends, as shown in FIG. 1. Each bar 20 has a central section 10, which in use will be clamped onto the bike at a central location, respective end sections 12, 14, which in use will be at a higher level than the central section 10 and to the ends of which hand grips and controls will be fitted, and respective intermediate or bent sections 16, 18, which extend between the central section 10 and each end section 12, 14. The bar 20 is first bent at each end of the central section 10, leading into the proximal end of the respective bent section 16, 18, and is bent again at the distal end of each bent section, leading into the respective end section 12, 14. The bar 20 is symmetrical. Such bars are invariably tubular, and of steel or aluminium, but that is not essential to the invention.
Conventional bars of this shape have a substantially constant external diameter (⅞″, namely 22.23 mm).
A crossbrace 21 is fitted between the respective bent sections 16, 18, for enhanced strength and rigidity. It is attached by a clamp (22 or 24) at each end. Two forms of clamp are known for this purpose.
The older form comprises a pair of C shaped clamp elements, each having a pair of opposed connection straps, which are bolted together in a facing disposition, with a bolt at each side of the handlebar. One of these bolts also secures the end of cross brace, which is formed into a flattened tongue or lug.
Because one of the bolts and the connection straps it secures projects inconveniently for motocross cycle riders, who need to be able to turn the handlebar right into the body in some instances, the aforesaid clamp has been superseded, at least on motocross bikes and the like, by a single U-shaped clamp body (22 or 24) which partially encircles the bar. This clamp 24 is generally secured by a single bolt 26, which also secures the end of the crossbrace 21, as shown in FIG. 2, which is again formed into a flattened tongue or lug 29. Alternatively, as shown in FIG. 1, such a clamp 22 may have elongate clevis arms and be secured by two bolts 23, 25, one of which secures the clamp body 22 to the bar 20, and the other of which secures the end of the crossbrace 21 to the clamp body 22, as described in U.S. Pat. No. 5,064,157.
Motorcycle handlebars are now known, as described, for example, in U.S. Pat. No. 5,117,708, U.S. Pat. No. 5,257,552, and U.S. Pat. No. 5,950,497, which are of similar overall configuration, but wherein the external diameter of the central section is enlarged (to 1⅛″, namely 28.58 mm) and the bent sections taper from their proximal ends, at or near the central section, to their distal ends, at or near the end sections, which remain at an external diameter of about ⅞″ (22.23 mm). Hitherto, such handlebars have not been fitted with crossbraces. They already have enhanced strength compared to the constant but smaller external diameter bars.
It is now desired to fit crossbraces to these latter bars, but it is difficult, with the style of clamps known hitherto, to clamp a tapering frustoconical surface so that there will be no slippage and simultaneously clamp the end of a crossbrace, bearing in mind that it is also important to have a wide area of contact between the bar and the clamp to minimise the risk of uneven wear or uneven stress leading to failure of the bar, and risk to life.